High-yield and straight-forward production of ammonia (13N) using a Siemens Eclipse HP cyclotron
Mateusz Synowiecki, Julie Bernard, Lars Perk
Radboudumc, Radboud Translational Medicine B.V., Nijmegen, The Netherlands
Oral Presentation
The authors declare no conflicts of interest
Ammonia (13N) ([13N]NH3) is used for myocardial perfusion imaging with PET. [13N]NH3 (t1/2 = 9.965 min) is most commonly produced by proton irradiation of water for injection containing a small amount of ethanol, i.e. via the 16O(p,α)13N nuclear reaction. The technology for producing 13N-NH3 with a Siemens Eclipse 11 MeV cyclotron with the old aluminum target design with a titanium window and a HPLC-pump has remained unchanged for years. This process results in certain manufacturing limitations for the users, like a low radioactivity production yield, relatively long processing times, and frequent maintenance intervals. It is critical to tackle these issues in order to achieve an efficient 13N-NH3 production method. We demonstrate the successful employment of the standard Siemens fluorine-18 tantalum water target combined with a havar window and a pressurized gas loading system for the production of 13N-NH3. This new method resulted in a far more efficient production process of 13N-NH3 (mean yield of 9.7 GBq at EOB, 273 MBq/µAsat) and in a final product with a high radiochemical and radionuclidic purity.